d2vm/README.md

# d2vm (Docker to Virtual Machine)

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*Build virtual machine image from Docker images*

The project is heavily inspired by the [article](https://iximiuz.com/en/posts/from-docker-container-to-bootable-linux-disk-image/) and the work done by [iximiuz](https://github.com/iximiuz) on [docker-to-linux](https://github.com/iximiuz/docker-to-linux).

Many thanks to him.

**Status**: *alpha*

[![asciicast](https://asciinema.org/a/520132.svg)](https://asciinema.org/a/520132)

## Supported Environments:

**Only building Linux Virtual Machine images is supported.**

**Starting from v0.1.0, d2vm automatically run build and convert commands inside Docker when not running on linux**.

## Supported VM Linux distributions:

Working and tested:

- [x] Ubuntu (18.04+)
- [x] Debian (stretch+)
- [x] Alpine
- [x] CentOS (8+)

Unsupported:

- [ ] RHEL

The program uses the `/etc/os-release` file to discover the Linux distribution and install the Kernel,
if the file is missing, the build cannot succeed.

Obviously, **Distroless** images are not supported. 

## Getting started

### Install from release

Download the latest release for your platform from the [release page](https://github.com/linka-cloud/d2vm/releases/latest).

Extract the tarball:

```bash
tar -xvzf <RELEASE-TARBALL-NAME>.tar.gz
```

Move the extracted *d2vm* binary to somewhere in your `$PATH` (`/usr/local/bin` for most users).

### Install from source

Clone the git repository:

```bash
git clone https://github.com/linka-cloud/d2vm && cd d2vm
```

Install using the *make*, *docker* and the Go tool chain:

```bash
make install
```

The *d2vm* binary is installed in the `$GOBIN` directory.

```bash
which d2vm

/go/bin/d2vm
```

### Converting an existing Docker Image to VM image:

```bash
d2vm convert --help
```
```
Convert Docker image to vm image

Usage:
  d2vm convert [docker image] [flags]

Flags:
      --append-to-cmdline string   Extra kernel cmdline arguments to append to the generated one
  -f, --force                      Override output qcow2 image
  -h, --help                       help for convert
      --network-manager string     Network manager to use for the image: none, netplan, ifupdown
  -o, --output string              The output image, the extension determine the image format, raw will be used if none. Supported formats: qcow2 qed raw vdi vhd vmdk (default "disk0.qcow2")
  -p, --password string            The Root user password (default "root")
      --pull                       Always pull docker image
      --raw                        Just convert the container to virtual machine image without installing anything more
  -s, --size string                The output image size (default "10G")

Global Flags:
  -t, --time string   Enable formated timed output, valide formats: 'relative (rel | r)', 'full (f)' (default "none")
  -v, --verbose       Enable Verbose output


```

Create an image based on the **ubuntu** official image:

```bash
sudo d2vm convert ubuntu -o ubuntu.qcow2 -p MyP4Ssw0rd
```
```
Pulling image ubuntu
Inspecting image ubuntu
No network manager specified, using distribution defaults: netplan
Docker image based on Ubuntu 22.04.1 LTS (Jammy Jellyfish)
Building kernel enabled image
Creating vm image
Creating raw image
Mounting raw image
Creating raw image file system
Copying rootfs to raw image
Setting up rootfs
Installing linux kernel
Unmounting raw image
Writing MBR
Converting to qcow2
```

You can now run your ubuntu image using the created `ubuntu.qcow2` image with **qemu**:

```bash
d2vm run qemu ubuntu.qcow2
```
```
SeaBIOS (version 1.13.0-1ubuntu1.1)


iPXE (http://ipxe.org) 00:03.0 CA00 PCI2.10 PnP PMM+BFF8C920+BFECC920 CA00



Booting from Hard Disk...

SYSLINUX 6.04 EDD 20191223 Copyright (C) 1994-2015 H. Peter Anvin et al
Now booting the kernel from SYSLINUX...
Loading /boot/vmlinuz... ok
Loading /boot/initrd.img...ok
[    0.000000] Linux version 5.4.0-109-generic (buildd@ubuntu) (gcc version 9)
[    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz ro root=UUID=b117d206-b8
[    0.000000] KERNEL supported cpus:
[    0.000000]   Intel GenuineIntel
[    0.000000]   AMD AuthenticAMD
[    0.000000]   Hygon HygonGenuine
[    0.000000]   Centaur CentaurHauls
[    0.000000]   zhaoxin   Shanghai

...

Welcome to Ubuntu 20.04.4 LTS!

[    3.610631] systemd[1]: Set hostname to <localhost>.
[    3.838984] systemd[1]: Created slice system-getty.slice.
[  OK  ] Created slice system-getty.slice.
[    3.845038] systemd[1]: Created slice system-modprobe.slice.
[  OK  ] Created slice system-modprobe.slice.
[    3.852054] systemd[1]: Created slice system-serial\x2dgetty.slice.
[  OK  ] Created slice system-serial\x2dgetty.slice.

...

Ubuntu 20.04.4 LTS localhost ttyS0

localhost login: 
```

Log in using the *root* user and the password configured at build time.

```
localhost login: root
Password:


Welcome to Ubuntu 20.04.4 LTS (GNU/Linux 5.4.0-109-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

This system has been minimized by removing packages and content that are
not required on a system that users do not log into.

To restore this content, you can run the 'unminimize' command.

The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.

root@localhost:~#
```

Type `poweroff` to shut down the vm.

### Building a VM Image from a Dockerfile

The example directory contains very minimalistic examples:

```bash
cd examples
```

*ubuntu.Dockerfile* :

```dockerfile
FROM ubuntu

RUN apt update && apt install -y openssh-server && \
    echo "PermitRootLogin yes" >> /etc/ssh/sshd_config

```

When building the vm image, *d2vm* will create a root password, so there is no need to configure it now.

Build the vm image:

The *build* command take most of its flags and arguments from the *docker build* command.

```bash
d2vm build --help
```

```
Build a vm image from Dockerfile

Usage:
  d2vm build [context directory] [flags]

Flags:
      --append-to-cmdline string   Extra kernel cmdline arguments to append to the generated one
      --build-arg stringArray      Set build-time variables
  -f, --file string                Name of the Dockerfile
      --force                      Override output image
  -h, --help                       help for build
      --network-manager string     Network manager to use for the image: none, netplan, ifupdown
  -o, --output string              The output image, the extension determine the image format, raw will be used if none. Supported formats: qcow2 qed raw vdi vhd vmdk (default "disk0.qcow2")
  -p, --password string            Root user password (default "root")
      --raw                        Just convert the container to virtual machine image without installing anything more
  -s, --size string                The output image size (default "10G")

Global Flags:
  -t, --time string   Enable formated timed output, valide formats: 'relative (rel | r)', 'full (f)' (default "none")
  -v, --verbose       Enable Verbose output

```

```bash
sudo d2vm build -p MyP4Ssw0rd -f ubuntu.Dockerfile -o ubuntu.qcow2 .
```

Or if you want to create a VirtualBox image:

```bash
sudo d2vm build -p MyP4Ssw0rd -f ubuntu.Dockerfile -o ubuntu.vdi .
```

### Complete example

A complete example setting up a ZSH workstation is available in the [examples/full](examples/full/README.md) directory.


### Internal Dockerfile templates

You can find the Dockerfiles used to install the Kernel in the [templates](templates) directory.

### TODO / Questions:

- [ ] Create service from `ENTRYPOINT` `CMD` `WORKDIR` and `ENV` instructions ?
- [ ] Inject Image `ENV` variables into `.bashrc` or other service environment file ?
- [x] Use image layers to create *rootfs* instead of container ?

### Acknowledgments

The *run* commands are adapted from [linuxkit](https://github.com/docker/linuxkit).